1. Neural Anatomy and Function

2. NERVOUS SYSTEMS Central nervous system Peripheral nervous system

3. CENTRAL NERVOUS SYSTEM p. 33 Brain –Cerebral Cortex/Cerebrum Motor cortex –Basal Ganglia/Diencephalon – sensory input –Cerebellum – motor control –Brain stem – sensory input Spinal Cord

4. PERIPHERAL NERVOUS SYSTEM Somatic –Sensory (Gamma) Nerves –Motor (Alpha) Nerves Autonomic [FYI] –Parasympathetic –Sympathetic

5. Spinal Nerves p. 35

7. NERVE ANATOMY A single nerve cell is called a neuron A bundle or group of neurons make up a nerve A nerve contains both afferent and efferent nerves

8. Afferent Neuron Carry impulse towards the CNS (e.g. sensory nerves) Synapse Towards CNS

9. Efferent Neuron Carry impulse away from the CNS (e.g. motor nerves) 1.Stimulatory 2.Inhibitory

10. NEURON ANATOMY Dendrite Cell Body Axon

11. AXON 1.Conduction 2.Myelin sheath 3.Synapse 4.Neurotransmitter

12. CONDUCTION Resting State: Na outside, K inside

13. CONDUCTION 1. Depolarization 2. Propagation3. Repolarization 4. Na K Pump

14. MYELIN SHEATH

15. SYNAPSE

17. Quick Time Movie

18. NEUROMUSCULAR JUNCTION

21. MOTOR UNIT Motor unit = one motor nerve + all the muscle fibers it innervates. Types –Fast (alpha -1) –Slow (alpha -2)

22. 1 2 3

23. MOTOR UNIT FastFastSlow

24. MUSCLE TENSION or FORCE or STRENGTH 1.Number of MU stimulated 2.Frequency of stimulation to each MU 3.Type of MU stimulated

25. MUSCLE STIMULATION: How does it begin?

26. 1.Volitional Control (Motor Cortex) 1.Motor cortex 2.Motor neurons 3.Muscles

27. 2. Reflex Control 1.Afferent neuron –Sensory neuron 2.Efferent neuron –Motor neuron

29. PROPRIOCEPTION & KINESTHESIS p. 37 Proprioception –The ability to sense the position and location and orientation and movement of the body and its parts Kinesthesis –The ability to feel movements of the limbs and body

30. PROPRIOCEPTION Proprioceptors of the joints and skin –Meissner’s corpuscles –Ruffini’s corpuscles –Pacinian corpuscles –Krause’s end-bulbs

31. PROPRIOCEPTION Proprioceptors of the muscles –Muscle spindles –Golgi tendon organs

32. Muscle Spindles

33. muscle spindle

35. Muscle Spindles Provide proprioception Sense the amount of stretch and the rate of stretch Reflexes involving the muscle spindles is how we ‘feel’ a movement was done correctly Spindles are a part of learning; we develop such reflexes as we practice skills and movements

36. Golgi Tendon Organs

38. Sensitive to muscle tension and active contraction Protect muscle from excess contraction force Stimulation of GTO an afferent impulse is sent to the central nervous system In turn, efferent impulses are sent to the… –Agonist muscle causing it to relax –Antagonist muscle causing it to contract

39. Neuromuscular Summary An example from baseball. A pitcher throws a curve ball to Sammy Sosa Sammy’s eyes see the ball coming towards him and is able to identify the pitch as a curve ball Sensory nerves (afferent) send that information to the CNS In the CNS the sensory nerve synapses with motor nerves The motor nerves in turn stimulates the muscles (deltoid and pectoralis major) required to swing the bat in the proper position to hit the ball

40. Neuromuscular Summary Inside the fibers of the deltoid and pectoralis major, calcium is released The calcium allows myosin heads to attach to actin When the heads swivel the fibers of the deltoid muscle will shorten The shortening of the fibers will pull on the humerus causing Sammy to swing the bat The muscle spindles “tell” the CNS when the arm is in the correct position If all goes as planned, the deltoid and pectoralis major will move his arms into a position to hit the ball

41. Neuromuscular Summary An example from weight training. A man is having his muscular strength tested on the bench press For his first lift, 50 pounds is put on the bar He will be using his pectoralis major muscle with has 500 motor units (300 slow twitch and 200 fast twitch) and his triceps muscle His CNS stimulates 280 motor units leading to his pectoralis major muscle (180 slow twitch and 100 fast twitch) End nerve ending stimulates a separate muscle fiber

42. Neuromuscular Summary Calcium is released, myosin attaches to actin and swivels. The pectoralis major and triceps muscles shortens and his arm extends outward raising the bar with 50 pounds on it. After a few minutes of rest, 100 pounds is place on the bar This time he stimulates 380 motor units (260 slow twitch and120 fast twitch) The weight is successfully lifted After a few minutes of rest, 150 pounds is place on the bar

43. Neuromuscular Summary This time he stimulates 460 motor units (280 slow twitch and 180 fast twitch) As the pectoralis major muscle contracts the GTO in the pectoralis major are stimulated They stimulate a sensory nerve leading to the CNS In the CNS, the sensory nerve synapses with a motor nerve that will inhibit (relax) the pectoralis major muscle The man is unable to successfully lift the 150 pounds.